4-Methylmorpholine → N-tert-butyl-5-methylisoxazole-3,4-dicarboximide

Participants

Reaction Steps

6.3 g (62.2 mmol) of methylmorpholine, 2.4 g (20 mmol) of dimethylaminopyridine and 14.6 g of a 50% strength solution of propanephosphonic anhydride (23 mmol) in dichloromethane were added dropwise in succession to 3.8 g (16.8 mmol) of 3-tert-butylaminocarbonyl-5-methylisoxazole-4-carboxylic acid in 150 ml of dichloromethane at -5° C. and the mixture was then refluxed for 6 hours. Working up was carried out as described above. 3.2 g (91%) of N-tert-butyl-5-methylisoxazole-3,4,-dicarboximide were obtained as a solid of melting point 48°-50° C. (Example No. 2.001).

Provenance & Evidence